Aviation formulae
Purchase an electronic flight computer, such as a Navtronic or Avstar. You just have to plug in the numbers, hit a key, and all the work will be done for you. It's too much time and brain damage, in my .02 opinion, to try to get a spreadsheet program to calculate these formulae for you.
Your good, old-fashioned E6B whizwheel can do the calculations you need to perform. It has conversion charts for F to C and is as easy to use as a sliderule.
I looked at FL000's site. No offense to him/her, but it brought back very painful memories of third semester h.s. algebra.